Fix the generated Cargo.toml after rustlings init

src/dev/update.rs

@@ -3,26 +3,22 @@ use std::fs;
 use anyhow::{Context, Result};
 
 use crate::{
+    cargo_toml::updated_cargo_toml,
     info_file::{ExerciseInfo, InfoFile},
     DEBUG_PROFILE,
 };
 
-use super::check::{append_bins, bins_start_end_ind};
-
 fn update_cargo_toml(
     exercise_infos: &[ExerciseInfo],
     current_cargo_toml: &str,
-    cargo_toml_path: &str,
     exercise_path_prefix: &[u8],
+    cargo_toml_path: &str,
 ) -> Result<()> {
-    let (bins_start_ind, bins_end_ind) = bins_start_end_ind(current_cargo_toml)?;
+    let updated_cargo_toml =
+        updated_cargo_toml(exercise_infos, current_cargo_toml, exercise_path_prefix)?;
 
-    let mut new_cargo_toml = Vec::with_capacity(1 << 13);
-    new_cargo_toml.extend_from_slice(current_cargo_toml[..bins_start_ind].as_bytes());
-    append_bins(&mut new_cargo_toml, exercise_infos, exercise_path_prefix);
-    new_cargo_toml.extend_from_slice(current_cargo_toml[bins_end_ind..].as_bytes());
-
-    fs::write(cargo_toml_path, new_cargo_toml).context("Failed to write the `Cargo.toml` file")?;
+    fs::write(cargo_toml_path, updated_cargo_toml)
+        .context("Failed to write the `Cargo.toml` file")?;
 
     Ok(())
 }
@@ -34,8 +30,8 @@ pub fn update() -> Result<()> {
         update_cargo_toml(
             &info_file.exercises,
             include_str!("../../dev/Cargo.toml"),
-            "dev/Cargo.toml",
             b"../",
+            "dev/Cargo.toml",
         )
         .context("Failed to update the file `dev/Cargo.toml`")?;
 
@@ -43,7 +39,7 @@ pub fn update() -> Result<()> {
     } else {
         let current_cargo_toml =
             fs::read_to_string("Cargo.toml").context("Failed to read the file `Cargo.toml`")?;
-        update_cargo_toml(&info_file.exercises, &current_cargo_toml, "Cargo.toml", b"")
+        update_cargo_toml(&info_file.exercises, &current_cargo_toml, b"", "Cargo.toml")
             .context("Failed to update the file `Cargo.toml`")?;
 
         println!("Updated `Cargo.toml`");